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  <title>Document</title>
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  <script>
    //1. split 把字符串 转换为 数组  和 join() 相反
    let str = 'pink$blue'
    const res = str.split('$')
    console.log(res);
    let str1 = '今天吃饭了吗'
    const res1 = str1.substring(2, 4)
    console.log(res1);
    const res2 = str1 .includes('吗')
    console.log(res2);
  </script>
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